Self-locking retaining rings, i.e., rings which possess the capability of securing themselves to smooth cylindrical surfaces such as those of grooveless shafts, spindles, pins and the like (for convenience hereinafter termed carrier members) solely by the friction grip which their inner edges exert on said surfaces, are known in the art, as evidenced by the patent to Heimann U.S. Pat. No. 2,574,034 Nov. 6, 1951. However, such known rings intended for assembly on grooveless carrier members suffer the disadvantage that, because of the narrow-width of the opening between their ends, they can be assembled on their cylindrical carrier members only by the so-called axial assembly procedure, which for the external form of such a ring involves spreading of the ring ends by a limited amount such that the ring inner-edge diameter is slightly greater than that of the carrier member and thereupon with care being taken not to overspread the ring and with the ring ends held spread apart, bodily shifting the ring body over the end of the carrier member and axially therealong to a desired or preselected position in which it is to serve as a parts-retaining or -locating shoulder, whereupon upon its release it self-locks itself in place.
Various attempts have heretofore been made to design a retaining ring having a width of gap enabling its radial assembly, i.e., assembly by first (usually manually) bringing the ring to a preselected position as aforesaid and thereupon forcing the ring downwardly over the carrier member, the width of gap between the ends of the ring and the spring nature of the metal from which the ring was fashioned permitting such movement. Generally speaking, such attempts resulted in a widely gapped ring having a so-called crescent-shaped ring body as disclosed and claimed in the patents to Feitl U.S. Pat. No. 2,491,306 dated Dec. 13, 1949 and/or Brozek U.S. Pat. No. 2,382,947 dated Aug. 4, 1945.
However, the crescent-shaped ring proved to be successful only on grooved carrier members, due to the fact that, because of its extreme gap width and relatively low section height, it lacked the capability of self-locking itself with the requisite security to grooveless carrier members and, while capable of being assembled in shaft grooves, it soon became evident that the crescent-shaped ring was suited to being assembled only in grooves of but shallow to moderate depth.